Apple announced today that there's a security hole in the High Sierra update (OSX 10.13). The issue is a blank root password.
We know that Apple is working on patching this as fast as possible, and we will push through the update as soon as it's available.
Since this only effects High Sierra, below are instructions to check your version and manually update your root password. Please call ArcLight Support at 617.379.5900 for assistance changing your root password, or follow the below instructions.​